The Role of Separation in the Identification of Trace Aroma Compounds

2011 ◽  
pp. 65-76 ◽  
Author(s):  
J. Lin ◽  
Y. Wang ◽  
P. L. Perry ◽  
E. Frerot ◽  
A. Rada ◽  
...  
Keyword(s):  
Aroma Compounds

Aroma in Fermented Beverages: The Role of NonConventional Yeasts

2017 ◽  
pp. 1-2
Keyword(s):  
Quality Assessment ◽  
Product Quality ◽  
Synergistic Effects ◽  
Aroma Compounds ◽  
Alcoholic Beverages ◽  
Sensory Thresholds ◽  
Fermented Beverages ◽  
Key Factor ◽  
The Individual

The aroma of alcoholic beverages is a key factor for product quality assessment and its acceptance by the consumers. The global aroma of fermented beverages is the result of the interaction of many different aroma compounds, either present above or below their sensory thresholds. Aromas below their sensory thresholds can sometimes be perceived due to the additive, enhancing or synergistic effects [1]. In this way, it is important not only to pay attention to the individual aromas but also to the multitude of interactions between them.

scholarly journals Free Amino Nitrogen in Brewing

Fermentation ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 22 ◽  
Author(s):  
Annie Hill ◽  
Graham Stewart
Keyword(s):  
Amino Acids ◽  
Free Amino ◽  
Amino Nitrogen ◽  
Aroma Compounds ◽  
Ethanolic Fermentation ◽  
Methods Of Analysis

The role of nitrogenous components in malt and wort during the production of beer has long been recognized. The concentration and range of wort amino acids impact on ethanolic fermentation by yeast and on the production of a range of flavour and aroma compounds in the final beer. This review summarizes research on Free Amino Nitrogen (FAN) within brewing, including various methods of analysis.

scholarly journals Role of Glycosidic Aroma Precursors on the odorant profiles of Grenache noir and Syrah Wines from the Rhone valley. Part 2: characterisation of derived compounds

OENO One ◽  
2009 ◽  
Vol 43 (4) ◽  
pp. 213
Author(s):  
Marie A. Segurel ◽  
Raymond L. Baumes ◽  
Dominique Langlois ◽  
Christine Riou ◽  
Alain Razungles
Keyword(s):  
Multivariate Analyses ◽  
Accelerated Aging ◽  
Natural Aging ◽  
Aroma Compounds ◽  
Varietal Differences ◽  
Aroma Precursors ◽  
Rhone Valley ◽  
Grape Varieties ◽  
Related Compounds

<p style="text-align: justify;"><strong>Aims</strong>: Grenache noir and Syrah are the predominant grape varieties in the French Rhone valley vineyard. This study aimed at identifying the odorants generated from glycoconjugates extracted from wines made with Grenache noir and Syrah.</p><p style="text-align: justify;"><strong>Methods and results</strong>: Synthetic model wines enriched with glycoconjugates, treated or not with enzymes, were stored at 45 °C for 3 weeks, or at 13 °C for 18 months. Aromas generated were extracted and analyzed by GC-Olfactometry (only samples from accelerated aging) and were further quantitatively determined by GC-MS. Analysis of the extracts allowed to identify 49 odorants, including 27 that could be aglycons, or related compounds, of glycoconjugates from the grapes. In addition, the active compounds were quantified in similar experiments led in conditions of natural aging for 18 months.</p><p style="text-align: justify;"><strong>Conclusion</strong>: The two varieties, Grenache noir and Syrah, were distinguishable by 14 odorant zones. Multivariate analyses (PCA) performed with the amounts of aroma compounds formed during both model and natural aging confirmed the effect of the glycosidase treatment on the acceleration of the aroma compounds formation and on the increase of the varietal differences of the wines.</p><p style="text-align: justify;"><strong>Significance and impact of study</strong>: GC-Olfactometry coupled with GCMS were good techniques to indentify and apreciate the odorants generated from glycoconjugates in the wines of Syrah and Grenache Noir, but in the context of a blend of odors, these techniques showed their limits and did not permit to determine the real impact of a molecule in the global aroma of the wine perceived by the taster. Other methods as additive techniques should be used to complete this study.</p>

Genetic Characterization of the Major Lactococcal Aromatic Aminotransferase and Its Involvement in Conversion of Amino Acids to Aroma Compounds

1999 ◽  
Vol 65 (11) ◽  
pp. 4873-4880 ◽  
Author(s):  
Liesbeth Rijnen ◽  
Sophie Bonneau ◽  
Mireille Yvon
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Physiological Role ◽  
Aromatic Amino Acids ◽  
Aroma Compounds ◽  
Gene Inactivation ◽  
Sequence Homologies ◽  
Branched Chain ◽  
Aromatic Aminotransferase

ABSTRACT In lactococci, transamination is the first step of the enzymatic conversion of aromatic and branched-chain amino acids to aroma compounds. In previous work we purified and biochemically characterized the major aromatic aminotransferase (AraT) of a Lactococcus lactis subsp. cremoris strain. Here we characterized the corresponding gene and evaluated the role of AraT in the biosynthesis of amino acids and in the conversion of amino acids to aroma compounds. Amino acid sequence homologies with other aminotransferases showed that the enzyme belongs to a new subclass of the aminotransferase I subfamily γ; AraT is the best-characterized representative of this new aromatic-amino-acid-specific subclass. We demonstrated that AraT plays a major role in the conversion of aromatic amino acids to aroma compounds, since gene inactivation almost completely prevented the degradation of these amino acids. It is also highly involved in methionine and leucine conversion. AraT also has a major physiological role in the biosynthesis of phenylalanine and tyrosine, since gene inactivation weakly slowed down growth on medium without phenylalanine and highly affected growth on every medium without tyrosine. However, another biosynthesis aromatic aminotransferase is induced in the absence of phenylalanine in the culture medium.

scholarly journals Influence of Prebiotic Fructans on Retronasal Aroma from Elderly Individuals

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2906
Author(s):  
Carolina Muñoz-González ◽  
Marine Brule ◽  
Christophe Martin ◽  
Gilles Feron ◽  
Francis Canon
Keyword(s):  
Transfer Reaction ◽  
Proton Transfer Reaction ◽  
Reaction Mass ◽  
Aroma Compounds ◽  
Aroma Release ◽  
Elderly Individuals ◽  
Perceived Intensity ◽  
The Impact ◽  
First Time

This study investigates for the first time the role of fructans with prebiotic effects (oligofructose and inulin) on retronasal aroma among elderly individuals. The impact of oligofructose (20% w/w) on retronasal aroma release was investigated using proton transfer reaction-mass spectrometry (PTR-MS) after 73 elderly individuals consumed aqueous solutions aromatized with five aroma compounds (pentan-2-one, nonan-2-one, hexan-2,3-dione, octanal and linalool). The influence of oligofructose and inulin (10% w/w) on the perceived intensity (n = 26) of two aroma descriptors (butter and floral) was also studied together with the possibility of a dumping effect on aroma evaluation due to the sweetness provided by the fructans. The results showed that the presence of oligofructose produced a significant reduction in retronasal aroma release, which could be generally explained by the physicochemical properties of aroma compounds. The presence of prebiotic fructans did not significantly affect the perceived intensity of butter and floral notes, although a dumping effect for the butter descriptor in the presence of oligofructose was observed. To conclude, these findings suggest that although fructans can exert an impact on retronasal aroma, they can be used at precise concentrations to increase the prebiotic fibre content of food products without affecting the aroma profile of foods.

Aroma in Fermented Beverages: The Role of Non-Conventional Yeasts

2017 ◽  
pp. 1-2
Keyword(s):  
Quality Assessment ◽  
Product Quality ◽  
Synergistic Effects ◽  
Aroma Compounds ◽  
Alcoholic Beverages ◽  
Sensory Thresholds ◽  
Fermented Beverages ◽  
Key Factor ◽  
The Individual

The aroma of alcoholic beverages is a key factor for product quality assessment and its acceptance by the consumers. The global aroma of fermented beverages is the result of the interaction of many different aroma compounds, either present above or below their sensory thresholds. Aromas below their sensory thresholds can sometimes be perceived due to the additive, enhancing or synergistic effects [1]. In this way, it is important not only to pay attention to the individual aromas but also to the multitude of interactions between them.

Role of dactinomycin in the improved survival of children with Wilms' tumor

JAMA ◽  
1966 ◽  
Vol 195 (12) ◽  
pp. 1005-1009 ◽  
Author(s):  
D. J. Fernbach
Keyword(s):  
Wilms Tumor

Role of the allergist in diagnosis and management of patients with uveitis

JAMA ◽  
1966 ◽  
Vol 195 (3) ◽  
pp. 167-172 ◽  
Author(s):  
T. E. Van Metre
Keyword(s):  
Diagnosis And Management
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